Caged fasteners such as caged nuts are frequently used in the manufacture of automobiles and other goods. A caged nut generally comprises a nut engaged in a structure that allows access to the nut bore, and provides the nut with a limited range of movement within the cage. In the manufacture of automobiles using caged nuts, the cage is welded onto the frame of the automobile and provides a nut at a selected location for the attachment of another part, such as a door, to the frame. The range of movement of the nut in the cage is provided so that the part being mounted on the frame may be adjusted relative to the frame during final assembly.
A caged nut provides advantages in that it can be assembled into a product framework during manufacture, so that the number of operations required in the final assembly of the product are reduced. If a caged nut was not provided in such situations, it would often be difficult to locate a nut by hand to receive a bolt used to fasten components such as a door onto a vehicle frame. In the usual practice in the automotive industry, the caged nut is spot welded on the frame prior to the application of rust inhibiting coatings and paint.
It has been found that welding the caged nut onto the frame can promote corrosion of the frame, since rust inhibiting coatings applied after welding may not penetrate into the space between the cage and the frame, thereby leaving bare metal parts which are susceptible to corrosion.
However, it is generally not good practice to weld to a coated or painted workpiece, since the coating will impede effective welding, and the welding will damage and disrupt any protective coatings applied to the workpiece. Accordingly, it has heretofore been necessary to mount the caged nut to the frame before painting.
In addition, the practice of welding a caged nut to the frame before painting often leads to the problem of paint clogged threads where a female threaded fastener is required. This causes problems in the subsequent mounting of a part to the fastener, since a screw will not easily fit into a paint clogged fastener.
Accordingly, the present invention provides a self-mounting fastener which is adapted to mount in an aperture in a framework or workpiece without welding, and which may be mounted after the application of coatings and paint to the workpiece.